Mpox virus, the latest global epidemic - an explainer

New Delhi: Mpox, previously known as monkeypox, is an infectious disease caused by the monkeypox virus (MPXV), a member of the Orthopoxvirus genus.

The World Health Organization (WHO) on Wednesday declared a global health emergency with Mpox spreading rapidly across 13 African countries, including Congo, where 14,000 cases and 524 deaths have been reported.

There are two distinct genetic clades of this virus, Clade I and Clade II. The disease, often characterised by painful rashes, fever, and swollen lymph nodes, primarily spreads through direct contact with infected individuals, animals, or contaminated materials.

Historically, the virus was first identified in 1958 in monkeys used for research in Denmark, with the first human case reported from Congo in 1970. After the eradication of smallpox in 1980, Mpox began to emerge in Central, East, and West Africa, leading to sporadic outbreaks. A significant global outbreak occurred between 2022 and 2023, primarily caused by the Clade IIb strain.

Mpox spreads from person to person through direct contact with infectious lesions, respiratory droplets, or contaminated objects like bedding or clothing. It can also be transmitted from animals to humans through bites, scratches, or consumption of infected animals. The virus enters the body through broken skin, mucosal surfaces, or the respiratory tract. High-risk groups include people with multiple sexual partners and those in close contact with infected individuals or animals.

Symptoms typically appear within 1-21 days after exposure and may last 2-4 weeks. The disease commonly starts with fever, muscle aches, and sore throat, followed by a rash that progresses through several stages, including macules, papules, vesicles, and pustules, before crusting over and falling off. The rash can appear anywhere on the body, including the face, mouth, genitals, and anus. Lymphadenopathy, or swollen lymph nodes, is a classic symptom of Mpox.

Diagnosing Mpox involves differentiating it from similar conditions like chickenpox, measles, and other skin infections. Polymerase chain reaction (PCR) testing of skin lesion material is the preferred diagnostic method. Blood testing is generally not recommended, and antibody detection methods may not be useful in distinguishing Mpox from other orthopoxviruses.

Treatment focuses on supportive care to manage symptoms and prevent complications. Vaccination, especially for high-risk groups like healthcare workers and men who have sex with men, is recommended to prevent infection. Several antivirals, such as tecovirimat, originally developed for smallpox, have been used to treat Mpox, and further studies are ongoing.

Preventing the spread of Mpox involves avoiding close contact with infected individuals, practicing good hygiene, and isolating infected persons until they are no longer contagious. Vaccination within four days of exposure can help prevent infection, and condoms can reduce but not eliminate the risk of transmission.

The global outbreak in 2022 led to the World Health Organization (WHO) declaring Mpox a Public Health Emergency of International Concern (PHEIC) on July 23, 2022. The outbreak primarily affected men who have sex with men, highlighting the importance of targeted public health interventions.

Mpox remains a concern due to its potential for severe complications, particularly in children, pregnant individuals, and those with weakened immune systems. Continued surveillance, vaccination, and public health efforts are crucial to controlling and preventing future outbreaks.